Toroidal coil winding machine

ABSTRACT

Herein disclosed is a toroidal coil winding machine suitable for manufacturing a toroidal coil of miniature size having a relatively small number of turns of an electric wire. The present winding machine employs a C-shaped ring in place of a conventional spool or shuttle, which ring is formed with a hole in the vicinity of one of its ends defined by the cut-away portion thereof. An electric wire is fed passing through the above hole to be helically wound on a toroidal core. The ring itself is rotatable passing through the bore of the toroidal core together with the wire passing through the hole thereof. Braking means is also provided in the present winding machine in the vicinity of the C-shaped ring for applying a frictional braking force to the wire, which is rotating together with the ring, to thereby prevent the wire from being slack.

United States Patent 1191 Fukushima Nov. 19, 1974 TOROIDAL COIL WINDING MACHINE [21] Appl. No.1 330,521

[30] Foreign Application Priority Data Primary Examiner-Billy S. Taylor Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [5 7] ABSTRACT Herein disclosed is a toroidal coil winding machine suitable for manufacturing a toroidal coil of miniature size having a relatively small number of turns of an electric wire. The present winding machine employs a C-shaped ring in place of a conventional spool or shuttle, which ring is formed with a hole in the vicinity of one of its ends defined by the cut-away portion thereof. An electric wire is fed passing through the above hole to be helically wound on a toroidal core. The ring itself is rotatable passing through the bore of the toroidal core together with the wire passing through the hole thereof. Braking means is also provided in the present winding machine in the vicinity of the C-shaped ring for applying a frictional braking force to the wire, which is rotating together with the ring, to thereby prevent the wire from being slack.

9 Claims, 13 Drawing Figures PATENTEL 1 91974 3,848,819

SHEET 20! 2 TOROIDAL COIL WINDING MACIHNE BACKGROUND OF THE INVENTION The present invention relates to a winding machine, and, more particularly, to a toroidal coil winding machine for helically winding an electric wire on a toroidal core so as to manufacture a miniature toroidal coil suitable for use in a pulse transformer.

A toroidal coil is a circular or toroidal core on which an electric wire is helically wound, as is well known in the art. When it is intended to manufacture a toroidal coil of miniature size, difficulties are often encountered in that every turn of the wire has to experience running or passing through a considerably restricted bore of the toroidal core.

For this reason, winding of the wire is conventionally carried out by a toroidal coil winding machine of remarkably complicated type. Moreover, the conventional winding machine is usually used to manufacture a toroidal coil of relatively large size having a large number of turns of the wire. When, therefore, the conventional machine is used to wind a relatively small number of turns, for instance, several to several dozen turns, then preparatory winding-up of the wire on a spool must be performed. This preparation consumes a major portion of time required to produce one toroidal coil. Thus, the conventional machine cannot be free from a drawback that the unnecessary preparatory step will invite a degraded production efficiency in comparison even with the manual winding.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toroidal coil winding machine suitable for manufacturing a toroidal coil of miniature size with a relatively small number of turns of an electric wire.

. Another object of the invention is to provide a toroidal coil winding machine having a simplified mechanism with a resultant efficient winding performance.

According to one feature of the present invention, a C-shaped ring is employed in place of a conventional spool. This C-shaped ring is formed with a hole, through which an electric wire to be wound is fed. The ring itself is rotatable passing through the bore of a toroidal core together with the wire passing through its hole.

According to another feature of the invention, braking means is disposed in the vicinity of the C-shaped ring for applying a frictional braking force to the wire, which is rotating together with the ring, to thereby prevent the wire from being slack.

Other objects and features of the present invention will be apparent from the description taken in connection with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut-away side elevation showing an exemplary toroidal coil winding machine of the present invention;

FIG. 2 is a side elevation showing a C-shaped ring to be employed in the winding machine of FIG. 1;

FIG. 3 is an enlarged side view taken along the arrow A of FIG. 2 showing one shape of the hole 1';

FIG. 4 is a partial view showing a mechanism for driving the C-shaped ring;

FIG. 5 shown a cross-sectional view of a C-shaped ring holder to be employed in the winding machine of FIG. 1;

FIGS. 6(a) to 6(e) are explanatory views showing the winding operations of the present invention;

FIG. 7 is an enlarged view showing braking means to be employed in the winding machine of FIG. 1;

FIG. 8 is a top plan view showing a part of a core rotating means to be employed in the winding machine of FIG. 1; and

FIG. 9 is an enlarged side view taken along the arrow A of FIG. 2 showing a second shape of the hole 1'.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, reference numerals l and 2 respectively designate a C-shaped ring and a C-shaped ring holder. The C-shaped ring 1 is a circular body with a portion removed, as is better seen from FIG. 2. This ring 1 is made of a heat-treated carbon steel or the like having its surfaces smoothly finished, and is formed with a hole I positioned in the vicinity of the removed portion, as shown in FIGS. 2 and 3. Through this hole 1' is fed an electric wire 9 to pass or run so as to be wound on a toroidal core 8. With reference especially to FIG. 3, it will be understood that the hole 1' has a rectangular or elliptical contour which is finished to have a smooth surface. A rectangular shape or capsullike shape is preferable when it is intended to wind a bundle of wires secured in parallel to each other on a toroidal core. Turning to FIG. 5, the C-shaped ring holder 2 is formed with an annular track 2 for holding and guiding therethrough the C-shaped ring 1. In the ring holder 2, an annular groove 2" is also formed which extends radially cutward from the annular track 2 for permitting the wire 9 to freely pass therethrough.

The ring holder 2 is also a circular body with a portion removed, leaving a C-shaped object. The removed portion divides the holder properly into two nearly complete semicircles which act as going and returning sides. These sides are shown in FIG. I as upper and lower halves, respectively. The ring holder 2 is further formed with a opening 4' positioned just above a point substantially diametrically opposite to the removed portion, that is, in the returning semicircle, so as to mount a brake 4 in the opening 4'. A plurality of other notches 3", which may preferable be equi-angularly spaced from each other, are further formed in the ring holder 2. The notches 3" are located so that the annular track 2' passes through them, as best seen in FIG. 1. In these notches 3" are mounted a corresponding number of paired driving rollers 3 and holding rollers 3' for rotating the C-shaped ring 1 through the annular track 2'. As best shown in FIG. 4, the driving rollers 3 are positioned to engage with one side surface of the ring 1, while the holding rollers 3 are juxtaposed with the rollers 3 and engage the opposite side surface of the ring I so as to hold the ring 1 in position in cooperation with the rollers 3. The holding rollers 3 are not shown in FIG. 1, but they would be located immediately above the ring 1 and directly above the driving rollers 3 in that view. It may be preferable that three to six of these paired rollers 3, 3' are arranged in the notches 3" of the ring holder 2.

Indicated at numeral 14 is a prime mover for driving the C-shaped ring 1, which mover 14 has its output shaft secured to a driving pulley 15. The driving force of the prime mover 14 is transmitted to a following pulley 16 through an endless belt 17 engaging with the pulleys 15, 16. To the following pulley 16 is secured a bevel gear 18 which meshes with a plurality of bevel gears (not numbered) respectively having their shaft secured to each of the driving rollers 3. With these arrangements, the driving force is finally transmitted to the driving rollers 3 via driving shafts.

The brake 4, which is mounted in the opening 4', acts to prevent the wire 9 from being slack, when the hole 1' of the C-shaped ring 1 moving toward the removed portion of the ring holder 2 is located over the returning semicircle, as has been described in the above. This action can be performed by making the wire 9 follow the outer periphery of the ring 1, that is, by retarding the rotation of the wire 9 which is then applied with a braking frictional force from the brake 4. This brake 4 is made of a synthetic rubber of hard type, and it is spaced from the outer periphery of the ring 1 at a distance of 0.02to 0.1 mm, namely, at a distance slightly smaller than a diameter of the wire 9 employed, as best shown in FIG. 7.

Turning now to the upper right-hand side corner of FIG. 1, biasing means (not numbered) is disposed outside of the brake 4 for biasing it toward the outer periphery of the ring 1. The biasing means includes a leaf spring 6 having one end attached to a brake lever 5. The other end of the leaf spring 6 is in sliding engagement with a pin 7 which is anchored in a ring holder fastening plate 16. The brake lever has an inner portion extending through a opening (not numbered) which is formed in the ring holder 2 and which merges into the opening 4. There it makes contact with the outer periphery of the brake 4, as better illustrated in FIG. 7. With reference to this figure, when the wire 9 runs into the space between the brake 4 and the C- shaped ring 1, the brake 4 is slightly lifted from the ring '1 by a distance determined by the difference between the diameter of the wire 9 and the spacing between the brake 4 and the ring 1. Since, however, the brake 4 is biased by the leaf spring 6 through the brake lever 5 toward the ring 1, the wire 9 is pressed on the outer periphery of the ring 1, resulting in the development of frictional forces between the brake 4 and the wire 9 and between the wire 9 and the ring 1. If, in this instance, the former frictional force is larger than the sum of the latter frictional force and the resistant force applied to the wire 9 when it is passing through the hole 1' of the ring 1, the wire 9 is free from any slackness. For example, the brake 4 may be made of silicone rubber, the outer periphery of the ring 1 may be finished to have a smoothly finished surface, and the wire 9 may be made of copper coated with a polyurethane resin. In this example, coefficient of the former friction has a value of about 0.5, while coefficient of the latter about 0.1, so that a sufficient braking force can be applied to the returning wire 9. During operation, on the other hand, the free end of the wire 9 is retained by retaining means or clamp 10 provided in the vicinity of the cutaway portion of the ring holder 2, as shown in FIG. 1.

Turning now to FIG. 8, a core rotating means (not generally numbered) is disposed at the cut-away portion of the ring holder 2 and acts partially to support the toroidal core 8 in position and partially to rotate it in synchronism with the rotation of the ring 1. The core rotating means includes three rollers each arranged at the vertex of an equalateral triangle so as to hold among them the toroidal core 8. As better shown in FIG. 1, one roller 11 of the three rollers is driven by a prime mover 12 by way of a worm wheel 13. The other two rollers 11 are idlers which merely support the toroidal core 8. These rollers 11, 11 are replacable by another group of different size in accordance with the diameter of the core 8.

Turning now the FIGS. 6(a) to 6(a), the clamp 10 is shown to be positioned at the inside of the C-shaped ring 1. This positioning is merely for illustrative purposes, as is the positioning shown in FIG. 8, in which the clamp 10 is shown to be positioned at the outside of the C-shaped ring 1.

Before entering into the actual winding operation, the cut-away portion of the C-shaped ring 1 is positioned in alignment with the cut-away portion of the ring holder 2, that is, with the rollers 11, 11'. At the same time the toroidal core 8 is inserted in the space defined by the rollers 11, 11. Then an electric wire 9 of a predetermined length is passed through the hole 1 of the ring 1, and one of the end of the wire 9 is retained by the clamp 10.

After completion of the above preparatory steps, the ring 1 is rotated in the direction of the arrow of FIGS. 6(a) to 6(e), and at the initial stage its portion formed with the hole I is passed through the bore of the toroidal core 8. The winding of the wire 9 will then proceed as the ring 1 is rotated in the order of FIGS. 6(a) to 6(c), until the hole 1' reaches the position B which is diametrically opposite to the toroidal core 8. This is because the wire 9 is smoothly drawn by the hole 1' which becomes remoter from the core 8 during the approaching stage of the hole 1 toward the position B.

When the hole 1 has arrived at the position B, it begins to move along the returning semicircle in which the distance between the returning hole 1 and the relatively stationary core 8 becomes smaller and smaller. As a result, the wire between the hole 1 and the core 8 is apt to be slack. Due to the braking frictional force from the brake 4, however, the wire 9 is retarded, as shown in FIGS. 6(d) and 6(e), to smoothly follow the outer periphery of the rotating ring 1, thus being free from any slackness.

In the meanwhile, the toroidal core 8 is rotated in synchronism with the rotation of the ring 1, so that the wire 9 can be helically wound on the core 8 without any overlapping or entanglement.

As an alternative, the brake 4 may be located at two or three portions of the returning semicircle of the ring holder 2, if desired. The brake 4 may also have such operation that it is normally positioned at a lifted level for refuge and approaches to the ring 1 in response to the rotation of the ring 1.

It should also be noted that suitable reduction gear mechanism, detecting mechanism for detecting turns of the wound wire, automatic stop mechanism associated with the detecting mechanism, and the like can suitably be provided in the winding machine of the present invention. It will be understandable that the crosssectional shape of the C-shaped ring, the contour of the annular track formed in the ring holder, and the mechanism for driving the ring and the core may be modified from the embodiments as shown in the appended drawmgs.

The winding machine according to the present invention should be appreciated in the following points:

In the present winding machine, with use of a ring holder of C-shape, the conventional spool can be replaced by a C-shaped ring, at the cutaway portion of which the toroidal core to be wound with a wire can be easily set. Moreover, preparation can be made by passing the wire through a hole of the ring and subsequently by retaining the free end of the wire, without winding up the wire on a spool as is customary in the conventional machine. Thus, the preparatory step is drastically simplified in the operation in which a relatively small number of turns of wire is wound on the toroidal core.

If, on the other hand, the above-mentioned turn detecting mechanism and the associated automatic stop mechanism are additionally incorporated into the present winding machine, then due to the simplified preparatory step one operator can handle two or three machines at a time. The operator can prepare one of the machines while the others are under the winding operation, so that the high production efficiency can be achieved.

Moreover, the C-shaped ring allows one to dispense with any spool or shuttle in the form of a groove for winding in advance the wire thereon, as is customary in the prior art. In the present machine, on the other hand, the ring holder is formed with an annular groove for guiding therethrough the rotating ring, so that the C-shaped ring itself need not have so much mechanical strength. This fact is advantageous in that the ring can be made very slim to thereby make it possible to wind a wire on a toroidal core having a restricted bore.

It should also be appreciated that the detection of the turns of wire can be easily made at the cut-away portion of the C-shaped ring with use of, for instance, a photometric element.

What is claimed is:

1. A winding machine for helically winding a wire on a toroidal core, comprising:

a C-shaped ring formed with a hole, through which the wire is fed, and rotatable to pass through the bore of the toroidal core together with the wire passing through the hole thereof;

a C-shaped ring holder formed with an annular track for holding and guiding therethrough said C- shaped ring, said ring holder furthermore having an annular groove extending radially outward of said annular track for permitting the wire to freely pass therethrough, said ring holder including rotating means disposed facing said annular track for rotating said C-shaped ring, and braking means disposed radially outward of said annular track for applying a frictional force to the wire rotating together with said C-shaped ring when the hole in said C-shaped ring is adjacent to said braking means;

core rotating means disposed adjacent to the ends of said ring holder for supporting the toroidal core in position and for rotating the same in synchronism with the rotation of said C-shaped ring; and

retaining means for retaining the free end of the wire when it is fed to be wound on the toroidal core.

2. A winding machine according to claim 1, wherein the hole of said C-shaped ring has a rectangular contour in its vertical view.

3. A winding machine according to claim 1, wherein the hole of said C'shaped ring has an elliptical contour in its vertical view, the periphery of said hole being smoothly finished to reduce the friction between the wire and the periphery of the hole.

4. A winding machine according to claim 1 and further comprising biasing means disposed outside of said braking means for biasing the same toward the outer periphery of said C-shaped ring.

5. A winding machine according to claim 4, wherein said biasing means bias said braking means towards a position spaced from the outer periphery of said C- shaped ring by a distance slightly less than the diameter of the wire.

6. A winding machine according to claim 1, wherein said braking means is positioned just above a point substantially diametrically opposite to the ends of said ring holder.

7. A winding machine according to claim 1, further comprising transmitting means for transmitting to the first-named rotating means a driving force received from a prime mover; wherein the first-named rotating means includes at least one driving roller engaging with said C-shaped ring and receiving the driving force for applying the same to said C-shaped ring, and at least one corresponding holding roller juxtaposed with said driving roller and engaging with said C-shaped ring for holding said C-shaped ring in position in cooperation with said driving roller.

8. A winding machine according to claim 7, wherein said transmitting means includes a pulley secured to the output shaft of the prime mover, an endless belt engaging with said pulley, a pulley engaging said endless belt for being driven by the prime mover through the firstnamed pulley and said endless belt, a bevel gear secured to the second-named pulley, and at least one corresponding bevel gear meshing with the first-named bevel gear and having its shaft secured to said driving roller.

9. A winding machine according to claim 1, wherein the second-named rotating means includes three rollers each arranged at the vertex of a triangle for holding among them the toroidal core, one of said three rollers being driven by a prime mover and the remaining two of the same being idlers for rotating the toroidal core in synchronism with the rotation of said C-shaped ring. =l 

1. A winding machine for helically winding a wire on a toroidal core, comprising: a C-shaped ring formed with a hole, through which the wire is fed, and rotatable to pass through the bore of the toroidal core together with the wire passing through the hole thereof; a C-shaped ring holder formed with an annular track for holding and guiding therethrough said C-shaped ring, said ring holder furthermore having an annular groove extending radially outward of said annular track for permitting the wire to freely pass therethrough, said ring holder including rotating means disposed facing said annular track for rotating said C-shaped ring, and braking means disposed radially outward of said annular track for applying a frictional force to the wire rotating together with said C-shaped ring when the hole in said C-shaped ring is adjacent to said braking means; core rotating means disposed adjacent to the ends of said ring holder for supporting the toroidal core in position and for rotating the same in synchronism with the rotation of said Cshaped ring; and retaining means for retaining the free end of the wire when it is fed to be wound on the toroidal core.
 2. A winding machine according to claim 1, wherein the hole of said C-shaped ring has a rectangular contour in its vertical view.
 3. A winding machine according to claim 1, wherein the hole of said C-shaped ring has an elliptical contour in its vertical view, the periphery of said hole being smoothly finished to reduce the friction between the wire and the periphery of the hole.
 4. A winding machine according to claim 1 and further comprising biasing means disposed outside of said braking means for biasing the same toward the outer periphery of said C-shaped ring.
 5. A winding machine according to claim 4, wherein said biasing means bias said braking means towards a position spaced from the outer periphery of said C-shaped ring by a distance slightly less than the diameter of the wire.
 6. A winding machine according to claim 1, wherein said braking means is positioned just above a point substantially diametrically opposite to the ends of said ring holder.
 7. A winding machine according to claim 1, further comprising transmitting means for transmitting to the first-named rotating means a driving force received from a prime mover; wherein the first-named rotating means includes at least one driving roller engaging with said C-shaped ring and receiving the driving force for applying the same to said C-shaped ring, and at least one corresponding holding roller juxtaposed with said driving roller and engaging with said C-shaped ring for holding said C-shaped ring in position in cooperation with said driving roller.
 8. A winding machine according to claim 7, wherein said transmitting means includes a pulley secured to the output shaft of the prime mover, an endless belt engaging with said pulley, a pulley engaging said endless belt for being driven by the prime mover through the first-named pulLey and said endless belt, a bevel gear secured to the second-named pulley, and at least one corresponding bevel gear meshing with the first-named bevel gear and having its shaft secured to said driving roller.
 9. A winding machine according to claim 1, wherein the second-named rotating means includes three rollers each arranged at the vertex of a triangle for holding among them the toroidal core, one of said three rollers being driven by a prime mover and the remaining two of the same being idlers for rotating the toroidal core in synchronism with the rotation of said C-shaped ring. 